Get them, and then dont wave to anyone. Just an observation lately on the river.
You bring up a good point it's not that people don't want to wave but when the boat is hauling azz it is not prudent to let go of the wheel or throttle and wave.
The passengers usually do but as the driver when your taking care of business you better focus on driving the boat. I'm sure you will agree with this rationale. If they are just cruising around then yes by all means common boating courtesy rules apply.
Respectfully,
KAP